Inbred and other generally defined rat strains are being increasingly used as biomedical research models. However, there are a number of problems associated with selecting and obtaining rat strains that can significantly affect research. The National Academy of Sciences proposes to appoint a committee to organize and hold a workshop in which internationally known geneticists and scientists in other fields will address these problems. Specific aims of this workshop are to encourage the use of standardized nomenclature for rats, resolve problems that have arisen because of the inappropriate use of nomenclature in naming rat strains, ensure high genetic quality of rats through genetic monitoring, encourage sharing of unique genetically defined strains by investigators, ensure continued availability of unique genetically defined rats through appropriate conservation measures, and develop a strategy for establishing communication between rat geneticists and rat-users outside the field of genetics to advance research using genetically defined rats. Workshop participants will discuss and update existing nomenclature rules, recommend solutions for problems that currently exist, and recommend a mechanism for continuous updating of the rules and handling of problems; develop criteria for genetic monitoring techniques and determine the frequency with which these tests should be done; discuss the rights and responsibilities of scientists sharing animals with others; adopt criteria for determining when genetically unique strains are worthy of conservation how they should be preserved; and develop a strategy for informing scientists in various fields of biomedical research about developments in rat genetics. It is anticipated that the workshop report will be published in ILAR News, Rat News Letter, Transplantation Proceedings, Journal of Immunogenetics, Laboratory Animal Science, Laboratory Animals (London), Experimental Animals (Japan), and selected other journals in appropriate fields of biomedical research such as Hypertension and Diabetes. The report will facilitate biomedical research by making a major contribution to the establishment of consistent, international nomenclature and criteria for sharing and preserving unique genetic rat stocks.